Add default admin user and role in ASP.Net Core

I am following a tutorial about roles but the default admin user is not created. The roles are created.

File Name: DbInitializerRepo

using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using ShoppingCart2023.Data;
using ShoppingCart2023.Models;

namespace ShoppingCart2023.DbInitializer
{
    public class DbInitializerRepo : IDbInitializer
    {
        private readonly UserManager<IdentityUser> _userManager;
        private readonly RoleManager<IdentityRole> _roleManager;
        private readonly ApplicationDbContext _context;

        public DbInitializerRepo(UserManager<IdentityUser> userManager, RoleManager<IdentityRole> roleManager, ApplicationDbContext context)
        {
            _userManager = userManager;
            _roleManager = roleManager;
            _context = context;
        }

        public void Initializer()
        {
            try
            {
                if (_context.Database.GetPendingMigrations().Count() > 0)
                {
                    _context.Database.Migrate();
                }
            }
            catch (Exception) 
            {
                throw;
            }

            if (!_roleManager.RoleExistsAsync(WebSiteRole.Role_Admin).GetAwaiter().GetResult()) 
            { 
                _roleManager.CreateAsync(new IdentityRole(WebSiteRole.Role_Admin)).GetAwaiter().GetResult();
                _roleManager.CreateAsync(new IdentityRole(WebSiteRole.Role_User)).GetAwaiter().GetResult();
                _roleManager.CreateAsync(new IdentityRole(WebSiteRole.Role_Employee)).GetAwaiter().GetResult();

                _userManager.CreateAsync(new ApplicationUser
                {
                    UserName = "ramitaherwahdan1978@gmail.com",
                    Email = "ramitaherwahdan1978@gmail.com",
                    Name = "Admin",
                    Address = "Al Manaseer Area",
                    City = "Abu-Dhabi",
                    PinCode = "123456"
                }, "Admin@123").GetAwaiter().GetResult();

                ApplicationUser user = _context.ApplicationUsers.FirstOrDefault(x => x.Email == "ramitaherwahdan1978@gmail.com");
                _userManager.AddToRoleAsync(user, WebSiteRole.Role_Admin).GetAwaiter().GetResult();

            }
            return;
        }
    }
}

the WebSiteRole:

namespace ShoppingCart2023
{
    public static class WebSiteRole
    {
        public const string Role_User = "Customer";
        public const string Role_Admin = "Admin";
        public const string Role_Employee = "Employee";
    }
}

File Name: ApplicationDbContext

using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;
using ShoppingCart2023.Models;

namespace ShoppingCart2023.Data
{
    public class ApplicationDbContext : IdentityDbContext
    {
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
            : base(options)
        {
        }

        public DbSet<Category> categories { get; set; }
        public DbSet<Product> products { get; set; }
        public DbSet<ApplicationUser> ApplicationUsers { get; set; }
    }
}